Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422698AbWLUE0v (ORCPT ); Wed, 20 Dec 2006 23:26:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422703AbWLUE0v (ORCPT ); Wed, 20 Dec 2006 23:26:51 -0500 Received: from smtp.osdl.org ([65.172.181.25]:36615 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422698AbWLUE0u (ORCPT ); Wed, 20 Dec 2006 23:26:50 -0500 Date: Wed, 20 Dec 2006 20:26:21 -0800 From: Andrew Morton To: john stultz Cc: Roman Zippel , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [RFC] HZ free ntp Message-Id: <20061220202621.8e147b1d.akpm@osdl.org> In-Reply-To: <1166579658.5594.6.camel@localhost> References: <20061204204024.2401148d.akpm@osdl.org> <20061205203013.7073cb38.akpm@osdl.org> <1165393929.24604.222.camel@localhost.localdomain> <20061206131155.GA8558@elte.hu> <1165956021.20229.10.camel@localhost> <1166037549.6425.21.camel@localhost.localdomain> <1166578357.5594.3.camel@localhost> <1166579658.5594.6.camel@localhost> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1550 Lines: 33 On Tue, 19 Dec 2006 17:54:18 -0800 john stultz wrote: > On Tue, 2006-12-19 at 17:32 -0800, john stultz wrote: > > On Wed, 2006-12-13 at 21:40 +0100, Roman Zippel wrote: > > > On Wed, 13 Dec 2006, john stultz wrote: > > > > > You don't have to introduce anything new, it's tick_length that changes > > > > > and HZ that becomes a variable in this function. > > > > > > > > So, forgive me for rehashing this, but it seems we're cross talking > > > > again. The context here is the dynticks code. Where HZ doesn't change, > > > > but we get interrupts at much reduced rates. > > > > > > I know and all you have to change in the ntp and some related code is to > > > replace HZ there with a variable, thus make it changable, so you can > > > increase the update interval (i.e. it becomes 1s/hz instead of 1s/HZ). > > > > Untested patch below. Does this vibe better with you are suggesting? > > And here would be the follow on patch (again *untested*) for > CONFIG_NO_HZ slowing the time accumulation down to once per second. I'm still awaiting a final-looking version of this patch, fyi. I don't understand whether this is a theoretical might-happen thing, or if NTP problems have actually been observed in the field? Either way, I'm sure the final changelog will clear that up ;) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/